Tyrosine kinase-2 gene polymorphisms are associated with ulcerative colitis and Crohn's disease in Turkish Population

Targeted Sequencing of Cytokine-Induced PI3K-Related Genes in Ulcerative Colitis, Colorectal Cancer and Colitis-Associated Cancer

Chronic relapsing inflammatory bowel disease is strongly linked to an increased risk of colitis-associated cancer (CAC). One of the well-known inflammatory carcinogenesis pathways, phosphatidylinositol 3-kinase (PI3K), was identified to be a crucial mechanism in long-standing ulcerative colitis (UC). The goal of this study was to identify somatic variants in the cytokine-induced PI3K-related genes in UC, colorectal cancer (CRC) and CAC. Thirty biopsies (n = 8 long-standing UC, n = 11 CRC, n = 8 paired normal colorectal mucosa and n = 3 CAC) were subjected to targeted sequencing on 13 PI3K-related genes using Illumina sequencing and the SureSelectXT Target Enrichment System. The Genome Analysis Toolkit was used to analyze variants, while ANNOVAR was employed to detect annotations. There were 5116 intronic, 355 exonic, 172 untranslated region (UTR) and 59 noncoding intronic variations detected across all samples. Apart from a very small number of frameshifts, the distribution of missense and synonymous variants was almost equal. We discovered changed levels of IL23R, IL12Rß1, IL12Rß2, TYK2, JAK2 and OSMR in more than 50% of the samples. The IL23R variant in the UTR region, rs10889677, was identified to be a possible variant that might potentially connect CAC with UC and CRC. Additional secondary structure prediction using RNAfold revealed that mutant structures were more unstable than wildtype structures. Further functional research on the potential variants is, therefore, highly recommended since it may provide insight on the relationship between inflammation and cancer risk in the cytokine-induced PI3K pathway.

Selective tyrosine kinase 2 inhibitors in inflammatory bowel disease

Recent significant advances have been made in the treatment of chronic inflammatory diseases with initiation of the era of biologics. However, an unmet medical need still exists for novel targeted therapies. Compared with biologics, Janus kinase inhibitors (JAKis) are a new drug class of orally administered small molecules that have been shown to efficiently modulate complex cytokine-driven inflammation in preclinical models and human studies. Unfortunately, serious adverse effects have been reported with the first introduced pan-JAKi, tofacitinib. Here, we review tyrosine kinase 2 (TYK2) signaling in the pathophysiology of inflammatory bowel disease (IBD), examine mechanisms of action of selective TYK2 inhibitors (TYK2is), and discuss the potential for these inhibitors in efforts to balance benefits and harms.

Association of TYK2 polymorphisms with autoimmune diseases: A comprehensive and updated systematic review with meta-analysis

Autoimmune diseases are characterized by the loss of self-tolerance, leading to immune-mediated tissue destruction and chronic inflammation. Tyrosine kinase 2 (TYK2) protein plays a key role in immunity and apoptosis pathways. Studies have reported associations between single nucleotide polymorphisms (SNPs) in the TYK2 gene and autoimmune diseases; however, results are still inconclusive. Thus, we conducted a systematic review followed by meta-analysis. A literature search was performed to find studies that investigated associations between TYK2 SNPs and autoimmune diseases (multiple sclerosis, systemic lupus erythematosus, Crohn’s disease, ulcerative colitis, psoriasis, rheumatoid arthritis, type 1 diabetes, and inflammatory bowel disease). Pooled odds ratios (OR) with 95 % CI were calculated using random (REM) or fixed (FEM) effects models in the Stata 11.0 Software. Thirty-four articles were eligible for inclusion in the meta-analyses, comprising 9 different SNPs: rs280496, rs280500, rs280523, rs280519, rs2304256, rs12720270, rs12720356, rs34536443, and rs35018800. Meta-analysis results showed the minor alleles of rs2304256, rs12720270, rs12720356, rs34536443, and rs35018800 SNPs were associated with protection against autoimmune diseases. Moreover, the A allele of the rs280519 SNP was associated with risk for systemic lupus erythematosus. Our meta-analyses demonstrated that the rs2304256, rs12720270, rs12720356, rs34536443, rs35018800, and rs280519 SNPs in the TYK2 gene are associated with different autoimmune diseases.

Differential regulation of JAK/STAT-signaling in patients with ulcerative colitis and Crohn’s disease

In 2018, the pan-Janus kinase (JAK) inhibitor tofacitinib was launched for the treatment of ulcerative colitis (UC). Although tofacitinib has proven efficacious in patients with active UC, it failed in patients with Crohn’s disease (CD). This finding strongly hints at a different contribution of JAK signaling in both entities. Here, we review the current knowledge on the interplay between the JAK/signal transducer and activator of transcription (STAT) pathway and inflammatory bowel diseases (IBD). In particular, we provide a detailed overview of the differences and similarities of JAK/STAT-signaling in UC and CD, highlight the impact of the JAK/STAT pathway in experimental colitis models and summarize the published evidence on JAK/STAT-signaling in immune cells of IBD as well as the genetic association between the JAK/STAT pathway and IBD. Finally, we describe novel treatment strategies targeting JAK/STAT inhibition in UC and CD and comment on the limitations and challenges of the new drug class.

Profile of Tofacitinib in the Treatment of Ulcerative Colitis: An Evidence-Based Review of Recent Data

Recent advances in the understanding of the pathophysiology of ulcerative colitis (UC) have led to the expansion of our therapeutic arsenal. Conventional treatment options, including aminosalicylates, corticosteroids, thiopurines, and calcineurin inhibitors, fail to control the disease in a significant proportion of patients. Approximately 25-50% of the patients treated with tumor necrosis factor antibodies (anti-TNFα) are primary and secondary non-responders to therapy. Tofacitinib is a novel orally administered small synthetic molecule that inhibits a homologous family of enzymes, termed Janus kinases that modulate multiple key cytokines involved in the pathogenesis of UC. Phase II and III trials showed promising results in UC, leading the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) to approve its administration for the induction and maintenance of remission in moderate-to-severe UC. Herein, we review tofacitinib for the management of UC, its mechanism of action pharmacokinetic properties, efficacy, and safety.

Systematic review with meta-analysis: efficacy and safety of oral Janus kinase inhibitors for inflammatory bowel disease

BACKGROUND

Janus kinase (JAK) inhibitors represent a novel therapeutic class for treatment of inflammatory bowel disease.

AIMS

To determine the efficacy and safety of JAK inhibitors compared to placebo for the treatment of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

PubMed, Embase and CENTRAL were systematically searched to November 1, 2018. Randomised placebo-controlled trials (RCTs) of JAK inhibitors in adult patients with CD or UC were eligible. Open-label extension studies without a placebo comparator arm were excluded. Clinical, endoscopic, and safety outcomes were extracted and rates relative to placebo were pooled using a random-effects model.

RESULTS

A total of 12 RCTs (5 CD, 7 UC) were included. Patients were randomised to placebo (n = 844), tofacitinib (n = 1882), filgotinib (n = 130), peficitinib (n = 176), upadacitinib (n = 387) or TD-1473 (n = 31). JAK inhibitor treatment was associated with induction of clinical remission in CD (RR, relative risk 1.38 [95% confidence interval CI 1.04-1.83], P = 0.025, I²  = 14%) and UC (RR 3.07 [95% CI 2.03-4.63], P < 0.001, I²  = 0%). In UC, JAK inhibitor treatment was associated with induction of endoscopic remission (endoscopic Mayo subscore MCSe = 0/1) (RR 2.43 [95% CI 1.64-3.59], P < 0.001, I²  = 27%) and mucosal healing (MCSe = 0) (RR 5.50 [95% CI 2.46-12.32], P < 0.001, I²  = 0%). JAK inhibitor treatment increased the risk of infection compared to placebo (RR 1.40 [95% CI 1.18-1.67], P < 0.001, I²  = 0%), particularly for herpes zoster.

CONCLUSIONS

JAK inhibitors are effective for inducing clinical remission in CD and induction of clinical and endoscopic remission in UC, although are associated with an increased risk of infectious complications.

GLIS3 and TYK2 Single Nucleotide Polymorphisms Are Not Associated with Dermatomyositis/Polymyositis in Chinese Han Population

AIM

Racial differences and genetic overlap have been shown to be responsible for the difference in susceptibility to dermatomyositis (DM)/polymyositis (PM) in a variety of populations. Single nucleotide polymorphisms (SNPs) in the GLI-similar 3 (GLIS3) and tyrosine kinase 2 (TYK2) genes have been associated with various autoimmune diseases. The aim of this study was to investigate whether SNPs in GLIS3 (rs7020673, rs10758593, and rs10814916) and TYK2 (rs280519, rs2304256, rs17000730, and rs280501) were associated with an increase in susceptibility to DM/PM in a Chinese Han population.

MATERIALS AND METHODS

SNPs in GLIS3 and TYK2 were analyzed in a cohort of 1017 patients with DM/PM and 1280 healthy controls using a Sequenom MassArray system. Association analyses were performed using the PLINK v1.07 software.

RESULTS

In our study, the GLIS3 polymorphisms rs7020673 and rs10758593 were initially found to be predisposing risk factors for PM and PM with interstitial lung disease (p < 0.05). Both rs7020673 and rs10758593 were associated with PM in both additive and dominant models (p < 0.05); however, these observed associations were not apparent after Bonferroni correction. Other SNPs examined in our study were not associated with susceptibility to DM/PM.

CONCLUSION

GLIS3 and TYK2 polymorphisms are not associated with DM/PM in the Chinese Han population. As associations of SNPs in these genes in patients with DM/PM have been previously reported in other populations, we may conclude that the lack of association in our study may be the result of differences in genetic background. Further studies in other populations are needed to confirm our findings.

The Future of Janus Kinase Inhibitors in Inflammatory Bowel Disease

Inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, are disabling conditions characterised by chronic, relapsing inflammation of the gastrointestinal tract. Current treatments are not universally effective or, in the case of therapeutic antibodies, are hampered by immune responses. Janus kinase inhibitors are orally delivered small molecules that target cytokine signalling by preventing phosphorylation of Janus kinases associated with the cytokine receptor. Subsequently, phosphorylation of signal transducers and activators of transcription that relay Janus kinase signalling and transcription of cytokines in the nucleus will be diminished. Key cytokines in the pathogenesis of inflammatory bowel diseases are targeted by Janus kinase inhibitors. Several Janus kinase inhibitors are in development for the treatment of inflammatory bowel diseases. Tofacitinib, inhibiting signalling via all Janus kinase family members, was effective in phase 2 and 3 trials in moderate-severe ulcerative colitis. GSK2586184, a Janus kinase 1 selective inhibitor, induced clinical and endoscopic response in ulcerative colitis; however, the study was discontinued at an early stage due to liver toxicity observed in systemic lupus patients receiving the drug. Filgotinib, a Janus kinase 1 selective inhibitor investigated in treatment of Crohn's disease, was superior to placebo. As adverse events associated with the broad immunological effect of these agents have been reported, the future application of these drugs is potentially limited. We will discuss the treatment efficacy of Janus kinase inhibition in inflammatory bowel diseases, how current Janus kinase inhibitors available target immune responses relevant in inflammatory bowel disease, and whether more specific kinase inhibition could be effective.

The efficacy of tyrosine kinase inhibitor dasatinib on colonic mucosal damage in murine model of colitis

BACKGROUND AND OBJECTIVE

Ulcerative colitis is an inflammatory condition of the colon in the gastrointestinal system. Currently, the most potent medications used for ulcerative colitis produce no response in 20-30% of cases. There is a need for more efficient and reliable medications. Tyrosine kinase inhibitors have shown efficacy in some inflammatory diseases. Although dasatinib, a tyrosine kinase inhibitor, suppresses proinflammatory cytokines in colonic tissue, there are a few cases of hemorrhagic colitis with dasatinib. There is no study investigating the effect of dasatinib on experimental colitis. We aimed to investigate the effect of dasatinib in a colitis model induced with acetic acid in our study.

METHODS

In the study, 24 male Sprague-Dawley rats randomly distributed into 4 groups of 6 rats each as control, dasatinib, colitis and dasatinib+colitis groups. For colitis induction, 4% acetic acid was used. Sacrificing of the rats was performed on the seventh day. Disease activity, morphologic and histological injury, superoxide dismutase, myeloperoxidase and malondialdehyde activity, TNFα and CD3 expression were assessed in colonic tissue.

RESULTS

Apart from malondialdehyde, significant difference in all parameters between the control and colitis groups was determined. Difference between the colitis and colitis+dasatinib groups was not significant in only weight loss and biochemical parameters. Though dasatinib does not fully resolve the changes in colitis, there was significant regression.

CONCLUSIONS

Dasatinib decreased the inflammation in a rodent model of colitis. It may be provide this effect by the suppression of TNFα. Dasatinib may be one of the treatment options for ulcerative colitis.